Re: [dm-devel] device mapper and resizing devices

From: Andy <genanr emsphone com>

To: device-mapper development <dm-devel redhat com>

Subject: Re: [dm-devel] device mapper and resizing devices

Date: Tue, 1 Mar 2005 16:22:45 -0600

On Tue, Mar 01, 2005 at 11:20:43PM +0100, christophe varoqui wrote:
> On Tue, 2005-03-01 at 15:03 -0600, Andy wrote:
> >I am using dm-multipath on non-partitioned (xfs) devices on a SAN. If I
> >resize the device, and rescan my path devices (i.e rescan /dev/sda,
> >/dev/sdb, /dev/sdc,/dev/sdd (all the same path)) the kernel sees the new
> >size of the individual devices, but the /sys/block/dm-0 device is still the
> >old size. I believe this is the reason why I cannot grow my xfs filesystem
> >without doing a reboot so that the dm device will have the new size. I'd
> >like to avoid unmounting and rebooting to resize the device. I haven't
> >played with lvm enough to feel comfortable using it. Is there any way to
> >get the dm device to be the proper size, or is this a bug, or a feature that
> >needs further discussion?
> >
>
> Runing "multipath" again, after rescans, should pick up the size change
> and adjust the device map.
>
multipath does, and prints the new size, but it is unable to add the target
to the dm table because dev_size in device-mapper is still the smaller size
and I get the "device x:yy too small for target" message
(/sys/block/dm-x/size still shows the old size, even when everything else
has the new size).
Andy